PROJECT SUMMARY The Clinical Core is located at the Tulane University School of Public Health and Tropical Medicine (SPHTM). The overall objective of the Core is to recruit 300 male human subjects (200 Caucasians and 100 African Americans, AA) for Projects 2 & 3 and offer expertise and support for clinical, translational and human study aspects of this P01 application. These human subjects will be selected to fall into top 20% or bottom 20% of the age- and ethnicity-matched population in their hip BMD values and also meet a series of our well established in- /ex-clusion criteria. These in-/ex-clusion criteria have been in use for years in the extensive publications for our geneomics/functional genomics studies of osteoporosis. These human subjects will also all be included in Project 1, for the integrative data analyses within individual projects and across Projects 1-3 in the Biostatistics and Bioinformatics Core. Recruitment will be performed in Tulane SPHTM at New Orleans. Recruitment steps include: screen for potential subjects through our ongoing funded large-scale Louisiana Osteoporosis Study (LOS) and through the existing LOS archive; contact potential subjects and schedule visits for those willing to participate; confirm eligibility, perform clinical examination and collect specimens. Currently, LOS contains >6,500 Caucasians and >4,500 AAs in archive, approximately ~40% of which are males. Most of them (>95%) signed consent to allow re-contact for future research opportunities. LOS is currently accumulating, on average, ~180 new Caucasian subjects and ~120 AA subjects each month to the archive. Steps in specimen collection are: perform phlebotomy to obtain 120 ml peripheral blood from each of the 200 Caucasian and 100 AA subjects; transfer the blood immediately to the Tulane CBG (Center for Bioinformatics and Genomics) wet labs for cell isolation (<5 minute walk from the phlebotomy site). The PI?s group has had a long history of successful recruitment for clinical and epidemiological studies. We will recruit 75 qualified male subjects (50 Caucasians and 25 AAs) during each of the Years 1-4. The total cohort will include 200 healthy Caucasian and 100 healthy AA males, aged 20-30, half of each ethnic group with high, and the other half with low BMD at the hip (top or bottom 20% in age- and ethnicity-matched population). High and low BMD subjects will be closely matched for age and weight. All the relevant anthropormetric, epidemiological, medical and pehneotypic information, which are standard in our extensive genetic epidemiology studies of osteoporosis, will be collected. The services provided by this Core are routine in our CBG and based on the LOS, have been successful for several of our previous (e.g., R01AR064421, R21AG027110, 2R01AR050496, and 5P50AR055081) and ongoing (e.g., R01 AR057049 and 1R01AR059781) NIH projects. We do not foresee any insurmountable problem.